Hi there,

this may be a common task but did not find any helpful hint nor an answer: is there any way to combine to arrays A and B into another one element-wise, i.e.:
C = [[A[1],B[1]], [A[2],B[2]],...,[A[N],B[N]]]
without doing a for loop?

Thanks,
jon

1. if parametric equations are
x0 = a^4, x1=a^3*b, x2=a^2*b^2, x3=a*b^3, x4=b^4

how to find ideal below

e12 = x0*x2-x1^2
e13 = x0*x3-x1*x2
e14 = x0*x4-x1*x3
e23 = x1*x3-x2^2
e24 = x1*x4-x2*x3
e34 = x2*x4-x3^2

2.
if let y_i = x_i/x0 for i = 1..4
how to find above parametrically by below equations
y1 = b
y2 = b^2
y3 = b^3
y4 = b^4

the functions about vector field plot is so terrible,

is there any method to get it beautiful, like mathematica or matlab?

more options is needed for arrow's position, length, angle and color.

is there a plan for it?

And, the scalar field plot in 2d is better than vector field plot, but in 3d, isosurface plot are still need to be enhanced.

If possible, the plots in Plotting Guide are all need improve.

f := x^2+y-z=0

f2:= y^2 +z-x = 0

after shift , solution shift too, can it be said it is invariant in parameter shift?

if not, any example to show a function which is invariant in parameter shift?

> solve(f);
/ 2 \
{ x = x, y = -x + z, z = z }
\ /
> f2 := y^2+z-x;
2
y + z - x
> solve(f2);
/ 2 \
{ x = y + z, y = y, z = z }
\ /
> f;
2
x + y - z = 0

Hello Maple


I am preparing for an examination in Calculus, but my worksheet in Maple 18 doesn't cooperate. 

A lot of my studypartners use Maple 16 and they have no problems. 


I meet the following error: 

- Error, (in solve) invalid input: hastype expects 2 arguments, but received 1


I'm totally sure, that I'm typing correctly, because I write just the same as my studypartners. 
So is it an error, which only is seen in Maple 18 and can I do anything to solve the problem?

Kind regards
Anders Kristensen

PS: I can't figure out how to add a picture

Hi there,

I would like to have an operator (in this case, the natural logarithm) applied to a list/array of points defined as:

ydata := [0.572594976618e-1, 0.327865007249e-1, 0.280821589546e-1, 0.114365745192e-1, 0.578537931608e-2, 0.139154661062e-2, 0.641467839994e-3, 0.18013801847e-3];

How can I apply Maple's ln() operator to the whole array (i.e. avoid to apply it to ydata [1], ydata [2], etc.)?

Thank you,

jon

Hello friends!

I 'm a student and I don't know a lot about Maple, so I would be really grateful if anyone could help me.

I want to solve a system of two equations and I have two unknowns, which are k and εα. However I don't know what I am doing wrong and I can't solve it.

I have attached my file.

Thank you very much in advance!agogos_2.mw

I want to solve maximize of equation,but the maximize failed to solve it,who can help me.thanks.

Download maximize.mw

Dear All,

I'm trying to solve the following in Maple.

minimize(int(0.1e-3+.5*t+0.2e-2*t^2-b*t-a, t = 0 .. 300), location = true)

But Maple told me that the answer is

Float(-infinity), {[{a = Float(infinity), b = Float(infinity)}, Float(-infinity)]}.

I really need to get a kind of numerical answer. Would it be possible? Please Help me!!

In brief the problem can be stated as follows:

Given dependent variables Q_i i=1,...,N and independent variables x_i, y_i, and z_i i=1,...,N

which are related via the following system of N linear equations with parameters P₁, P₂ and P₃ :

Q_i = P₁x_i+P₂y_i+P₃z_i   i=1,...,N

How to find the optimal values of  P₁, P₂ and P₃ which satisfy the above system of linear equations subject to the following constraints:

P_i>=0   i=1,2,3

and  P₁>=P₂P₃

 Without the requirement of P₁>=P₂P_3, the problem can be solved with the Non-negative Least Squares Method of Lawson and Hanson.  But with this additional constraint, I am stuck.  

Your suggestions are welcome.

I'd like to plot the following inequalities:

sqrt(x)<=1/sqrt(2)

1/sqrt(2)<sqrt(x)<=1/sqrt(2)

Hey!

I have this MATLAB script, but as I work in Maple, I'll need to translate it to Maple. 
I know how to define symbols and functions, but I don't know which Maple commands to use, of if it needs to be done in another way, so the problem is translating from " dZ = [dx; dy; ax; ay; dm];" and down.

Any help would truly be greatly appreciated! Thank you!  

This is the script:

function dZ = meteor_step(~, Z)

  P = 1.2; % initial atmospheric pressure
  H = 1.39E-4; % scale height of atm pressure
  E = 8.11131859E6; % evaporation energy
  D = 1; % drag constant
  G = 9.814; % acceleration due to gravity
  PM = 3.3E3; % density of the meteor
  
  S = 3.986E14; % standard gravitational parameter of Earth (G*M)
  R = 6.3674447E6; % radius of the Earth (meters)

  x = Z(1);  
  y = Z(2);
  dx = Z(3);
  dy = Z(4);
  m = Z(5);
  
  atm = P*exp(-y*H);

  v = sqrt(dx^2+dy^2);

  area = pi * ( (3*m)/(4*PM) )^(2/3);

  dist = sqrt(x^2+y^2);
  Gv = -9.8;

  accel = -(D*atm*area)/m*v;
  ax = accel * dx;
  ay = accel * dy + Gv;
  

  dm = -(atm*v^3*area)/(2*E);
  
  dZ = [dx; dy; ax; ay; dm];
  
end

[t, R] = ode45(@meteor_step, [0 250], [0, 100000, 100, -300, 25]);

x = R(:,1);
y = R(:,2);

dx = R(:,3);
dy = R(:,4);

v = (dx.^2+dy.^2).^(1/2);

m = R(:,5);

figure(1);
plot(t, y);
  title('Meteor Kinematics: Height vs Time');
  xlabel('Time elapsed (s)');
  ylabel('Height (m)');

figure(2);
plot(x, y);
  title('Meteor Kinematics: Horizontal vs Vertical Position');
  xlabel('Horizontal (m)');
  ylabel('Vertical (m)');

figure(3);
plot(t, v);
  title('Meteor Kinematics: Speed vs Time');
  xlabel('Time elapsed (s)');
  ylabel('Absolute speed (m/s)');

figure(4);
plot(t, m);
  title('Meteor Kinematics: Mass vs Time');
  xlabel('Time elapsed (s)');
  ylabel('Mass (kg)');

  
figure(5);
plot(t, dy);
  title('Vertical Velocity vs Time');
  xlabel('Time elapsed (s)');
  ylabel('Vertical velocity (m/s)');

temp = abs(y - 52900);
[~, index] = min(temp);
  
t(index)
dx(index)/1000
dy(index)/1000

I've got a worksheet in which I have invested many hours of CPU execution time and if the computer goes down, or Maple fails for some reason, I'll lose it all.

If this happens I would like to be able to continue the calculation from where I left off.

By saving the worksheet periodically, I can save all the commands, but not the results, so if I have to restart, I'll have to wait many hours before the worksheet catches up to where it left off.

In ancient versions of Maple, you used to be able to save an executed worksheet including results (I sort of remember that you wrote a file with the extension ".M")  but the new help pages say that is now different from what it used to be. Obviously I can "save" individual symbols to a file, but for a complicated worksheet  that gets complicated.

I've read about "maplet" files, but that doesn't seem to fill the bill either.

So, is there any simple way to save a worksheet so you can continue seamlessly from where you left off after a crash, with all the previous results intact?

I have the following situation:

HB:=Bend(L,a,n);

Bend is a proc, that returns a Record with info based on its parameters. I would like to get access to the name I assign to (i.e. HB) in the proc. Any chance?

Mac Dude

PS: I can of course kludge things by adding an argument to the proc Bend. But I'd like to avoid that.

Hi,

I'm trying to solve the following differential equation numerically with dsolve:

but dsolve gives me this error:

> res := dsolve(DGL, numeric, parameters = [y0, A, B, C, E]);
Error, (in DEtools/convertsys) unable to convert to an explicit first-order system

I think the problem is that I use the wrong solver. Does Maple provide a solver which is capable of solving this kind of equations (nonlinear ODE)?

Thanks in advance!